Labs ✏ AP Biology

Rucete ✏ AP Biology In a Nutshell

22. Labs

This chapter summarizes 13 common lab investigations that align with the six core science practices of AP Biology. These labs help build experimental design, data analysis, and reasoning skills tested on the AP exam.



Core Science Practices

• Explaining biological concepts

• Analyzing visual representations

• Designing experiments and identifying variables

• Graphing and interpreting data

• Performing statistical analysis (e.g., chi-square, confidence intervals)

• Justifying claims using evidence

Lab 1: Artificial Selection

• Investigates how selection affects phenotypes over generations (e.g., Fast Plants and trichome number)

• Students select plants with highest trichome count to breed next generation

• Bar graphs with 95% confidence intervals are used to evaluate change

• Non-overlapping intervals suggest significant difference between generations

Lab 2: Hardy-Weinberg

• Uses simulations or spreadsheets to model allele frequencies

• Assumes no evolution (5 conditions met)

• Formulas: p + q = 1 and p² + 2pq + q² = 1

• Students alter variables to observe genetic drift, migration, or selection

Lab 3: BLAST (Bioinformatics)

• Uses online BLAST tool to compare gene sequences and determine homology

• Fewer nucleotide differences = closer evolutionary relationship

• Data used to revise hypotheses and construct phylogenetic trees

Lab 4: Diffusion and Osmosis

• Models water movement using agar cubes, dialysis tubing, and plant tissue

• Surface area-to-volume ratios are examined for diffusion efficiency

• Dialysis tubing used to simulate membranes; glucose, iodine, starch observed

• Water potential concepts and solute concentration calculations applied

• Potato cube mass changes used to estimate isotonic point (x-intercept)

Lab 5: Photosynthesis

• Floating leaf disk assay measures oxygen production

• Disks sink in bicarbonate solution, float when oxygen produced via photosynthesis

• Time for 50% of disks to float (ET50) = photosynthetic rate

• Conditions like light intensity and CO₂ availability are tested

Lab 6: Cellular Respiration

• Uses respirometers with potassium hydroxide (KOH) to measure O₂ consumption

• Small organisms (seeds, insects) used

• Data graphed over time; temperature effects tested

Lab 7: Mitosis and Meiosis

• Part 1: Students model mitosis to learn phases and outcomes

• Part 2: Chi-square used to analyze treated vs. untreated cells

• Part 3: Karyotype analysis compares normal and cancerous cells

• Part 4: Students model meiosis to explore segregation, assortment, recombination

• Part 5: Sordaria recombination data used to calculate gene distances

Lab 8: Bacterial Transformation

• Uses pGLO plasmid to transform E. coli bacteria

• Plasmid contains genes for GFP (fluorescence), ampicillin resistance, and an arabinose-activated promoter

• Only transformed bacteria grow on ampicillin plates

• Arabinose activates GFP expression → glowing colonies

• Results demonstrate gene expression, selection, and transformation efficiency

Lab 9: Restriction Enzymes and Gel Electrophoresis

• Restriction enzymes cut DNA at specific sequences → different-sized fragments

• Fragments are separated by gel electrophoresis based on size

• Smaller fragments travel farther through gel

• Used to analyze DNA, construct plasmids, or verify transformation

Lab 10: Energy Dynamics

• Students build food chains or webs and calculate energy transfer

• Trophic levels analyzed with respect to biomass and energy loss

• Energy pyramid constructed using real or hypothetical data

Lab 11: Transpiration

• Uses potometers to measure water loss through plant leaves

• Environmental variables tested (light, humidity, wind, temperature)

• Stomatal density and water potential concepts applied

Lab 12: Animal Behavior

• Pill bugs (isopods) used to study choice behavior (e.g., moisture, temperature, light)

• Chi-square test used to determine if distribution is random or significant

• Reinforces experimental design and hypothesis testing

Lab 13: Enzyme Activity

• Catalase breaks down H₂O₂ → H₂O and O₂

• Rate of reaction measured by foam height or time-based color change

• Variables tested: temperature, pH, substrate concentration, inhibitors

• Results used to explore enzyme kinetics and protein structure-function relationships

In a Nutshell

The AP Biology labs build core science skills while reinforcing key content. Students design and analyze experiments, apply statistical tools, and connect theory to practice. These investigations span evolution, genetics, molecular biology, physiology, and ecology—giving students authentic insights into the scientific process.

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